Various kinds of exposure apparatus are used in lithographic processes for manufacturing semiconductor elements and so forth. Step-and-repeat type projection apparatuses, such as step-and-repeat type projection exposure apparatuses (so-called “stepper”), and step-and-scan type projection exposure apparatuses (so-called “scanning stepper”) form the mainstream of exposure apparatuses.
With the advancement of large-scale integration and higher speeds of CPU processors and larger capacities of semiconductor memory, the demand for fine patterning of resists formed on wafers has been rapidly increasing, and higher exposure precision is becoming a requirement in such exposure apparatuses. Such apparatuses are used in the mass production of devices, and consequently, high throughput is also being demanded as a requirement in exposure apparatuses. The exposure precision and the throughput have been improved by enhancing the resolving power by increasing the numerical aperture (NA) of a projection optical system and by using shorter exposure wavelengths of the exposure light, by improving the position controllability and increasing the acceleration of the reticle stage or the wafer stage.
However, the shape and the weight of the projection optical system are enlarged when the NA of the projection optical system is increased, and vibrations increase when the acceleration of the reticle stage is increased. Thus, the increase in vibrations is suppressed by modifying the configuration of frames that supports the projection optical system, stages and the like, by elaborating displacement of vibration suppression devices, and the like, as disclosed in Japanese Unexamined Patent Application, First Publication No. 2002-305140.
However, the aforementioned techniques are directed to suppressing the occurrence of vibrations, and are not directed to directly improving the rigidity of the frames. Accordingly, to support the further increase in the NA of the projection optical system and the increase in the acceleration of the stage, the frames necessarily have to be made larger. There is, however, a limit on increasing the size of the frames because of restrictions in the installation location and the transportation of the exposure apparatus.
If the acceleration of the stage and the NA of the projection optical system are improved in order to form fine patterns, the rigidity of the frames is reduced relatively compared to the conventional case. As a result, the vibrations increase, and instead, the formation of fine patterns becomes difficult, which present a problem.